JP2004232922A - Heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the size of a heat exchanger having a heat absorbing group formed of a plurality of heat absorbing pipes 13a to 13d absorbing the heat of burned exhaust gas from a gas burner and allowing heated fluid to flow therein stacked on each other in the crossed state and a casing 50 surrounding the heat absorbing pipe group. <P>SOLUTION: The crossed portions R of the heat absorbing pipes 13a to 13d are formed flat in the stacked direction. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a heat exchanger for heating a fluid to be heated, such as water, and can be used as, for example, a heat exchanger for a water heater or a bath pot.
[0002]
[Prior art]
FIG. 8 shows a conventional heat exchanger incorporated in a water heater, and more specifically, a heat exchanger for recovering latent heat of a condensing water heater shown in FIG. 9 which absorbs latent heat in addition to sensible heat of combustion exhaust gas from a gas burner. It is sectional drawing of the principal part of container (1) (refer patent document 1).
In this device, heat-absorbing pipes (13a) and (13b) through which water as a fluid to be heated flows are disposed in the heat exchanger (1), and the heat-absorbing pipes (13a) and (13b) have a surface area. It is made of a flexible corrugated tube to enlarge and secure thermal efficiency.
[0003]
One of the heat absorbing pipes (13a) is bent so as to meander in a plane parallel to the plane of the paper of FIG. 8 (hereinafter, referred to as a "meandering surface"), thereby forming an arc-shaped folded portion (R). (R) and a linear portion (S) following both ends thereof. The other heat absorbing pipe (13b) is also bent in the same waveform as described above.
The heat absorbing pipes (13a) and (13b) are overlapped in a direction perpendicular to the meandering surface, and the heat absorbing pipes (13a) and (13b) are arranged so as to be shifted from each other by a half pitch in the wavelength direction of the waveform. Is established.
In this device, since the heat absorbing pipes (13a) and (13b) are arranged in an overlapping state, the dimension of the heat exchanger (1) in the overlapping direction can be reduced to some extent.
[0004]
[Patent Document 1]
JP 2001-241873 A (FIGS. 1 and 3)
[0005]
[Problems to be solved by the invention]
However, in the above-mentioned conventional device, there is a problem that the heat exchanger (1) cannot be sufficiently reduced in size because the heat absorbing pipes (13a) and (13b) are simply overlapped.
The present invention has been made in view of such a point,
`` A group of heat absorbing pipes stacked in a state where a plurality of heat absorbing pipes that absorb the heat of the combustion exhaust gas from the gas burner and through which the fluid to be heated flows intersect,
It is an object of the present invention to provide a heat exchanger having a casing that surrounds the heat absorbing pipe group, and providing a heat exchanger that is more compact than the above-described conventional one.
[0006]
[Means for Solving the Problems]
[1]
The technical means of the present invention for solving the above problems is as follows:
"The intersecting portions in each of the heat absorbing pipes are flattened in the overlapping direction".
According to the above technical means, since the heat absorbing pipes are superimposed at the flattened portion, the size of the heat absorbing pipe group as a whole in the superimposing direction is further reduced as compared with the non-flattened one, For this reason, the size can be further reduced as compared with the above-described conventional heat exchanger.
[0007]
In addition, the amount of combustion exhaust gas that does not exchange heat with the endothermic pipe is reduced, and the effect of improving thermal efficiency is produced. That is, when the heat absorbing pipes are arranged at intervals in the overlapping direction, the combustion exhaust gas passes through the space without contacting the heat absorbing pipes, whereby the heat absorbing pipe and the heat The amount of combustion exhaust that is not replaced increases. On the other hand, in the present invention, since the overlapping portion of the heat absorbing pipe group is flattened, the heat absorbing pipes are more densely arranged than the above-described conventional one, and accordingly, The amount of waste combustion exhaust discharged without contacting the heat absorbing pipe is reduced as compared with the conventional one having a lower arrangement density. That is, the flowing combustion exhaust wraps around to the back side of each heat absorbing pipe, thereby improving thermal efficiency.
[0008]
[2]
In the above item 1,
`` Each heat absorbing pipe has a shape meandering in a waveform in one meandering plane,
The heat absorbing pipes are sequentially stacked in a direction perpendicular to the meandering surface, and the heat absorbing pipes adjacent to each other in the overlapping direction are displaced in the wavelength direction of the waveform. Because it is meandering, it is longer than a straight pipe, and the thermal efficiency is improved accordingly.
[0009]
[3]
In the above paragraph 2,
"The heat-absorbing pipes are formed of corrugated pipes bent in the same waveform, and the arc-shaped folded portion and the straight portion following the end of the arc-shaped folded portion are alternately and repeatedly repeated. It is composed in
The flattened portion is the arc-shaped folded portion '', in which the heat absorbing pipes are formed in the same shape, so that the manufacturing efficiency is improved as compared with the case where heat absorbing pipes of different shapes are manufactured, Parts can be shared.
[0010]
[Item 4]
In the above item 3,
`` Each arc-shaped folded portion is located in the casing,
In the case where the inner wall of the casing is pressed against the outer circumference of each of the arc-shaped folded portions, the arc-shaped folded portion is stably pressed against the inner wall of the casing. Therefore, it is possible to suppress the vibration sound of each heat absorbing pipe caused by the water hammer phenomenon when the fluid to be heated suddenly stops.
[0011]
[5]
In the above items 1 to 4,
In the "the heat absorbing pipes are fixed to each other at the intersecting portion", the fixing can prevent the heat absorbing pipes from being displaced from each other, and the interval between the heat absorbing pipes can be increased over a long period of time. Since it can be maintained at an appropriate interval, it is possible to prevent a decrease in thermal efficiency over time.
[0012]
【The invention's effect】
The invention of the present application has the following specific effects because of the above configuration.
Since the size of the entire heat absorbing pipe group in the overlapping direction is smaller than that of the conventional one, the heat exchanger can be further downsized.
Further, as described above, the combustion exhaust gas easily flows to the back side of each heat absorbing pipe with respect to the exhaust gas flow, thereby reducing the amount of the combustion exhaust gas discharged without coming into contact with the heat absorbing pipe. Is improved.
[0013]
In the case of the third item, since the heat absorbing pipes are formed in the same shape, parts can be shared.
[0014]
According to the fourth aspect, it is possible to suppress the vibration noise of each heat absorbing pipe caused by the water hammer phenomenon when the fluid to be heated suddenly stops.
[0015]
In the case of the fifth item, since the intervals between the heat absorbing pipes can be maintained at appropriate intervals over a long period of time, it is possible to prevent a decrease in thermal efficiency over time.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, the above-described embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a longitudinal sectional view of a condensing water heater to which a heat exchanger according to an embodiment of the present invention is applied.
In this condensing water heater, a gas burner (B) is housed in a combustion box (C) connected above an air supply fan (F) provided in a main body case (H). A main heat exchanger (2) for absorbing sensible heat from the combustion exhaust gas of the gas burner (B) is connected above the box (C), and the main heat exchanger (2) absorbs the sensible heat. A heat absorbing pipe (21) is provided. The heat absorbing pipe (21) is composed of a single copper pipe meandering back and forth with respect to the paper surface of FIG. 1, and hot water heated and heated from a downstream end (22) thereof. It is spilled.
[0017]
The heat exchanger to which the present invention is applied is implemented as a sub heat exchanger (5) for recovering latent heat from the combustion exhaust gas of the gas burner (B).
Hereinafter, the structure of the sub heat exchanger (5) will be described in more detail.
[0018]
[Overall structure]
As shown in FIGS. 1 and 2, the auxiliary heat exchanger (5) is provided with heat absorbing pipes (13a) to (13d) through which tap water as a fluid to be heated flows and absorbs latent heat from the combustion exhaust gas of the gas burner. And a casing (50) for carrying out.
[0019]
[Casing (50)]
The casing (50) is formed in a rectangular box shape as a whole. Therefore, the casing (50) is composed of the front and rear plates (53) and (54) and the side plates (51) and (52) assembled in a rectangular frame shape, and the upper open rectangular frame assembled by the side plates (51) and (52). And a top plate (55) for closing the top of the top plate.
[0020]
In the casing (50), an exhaust guide plate (56) disposed above the heat absorbing pipes (13a) to (13d), and a drain guide for receiving drain dripped from the heat absorbing pipes (13a) to (13d) ( 57) are provided. The drain guide (57) is inclined so as to become lower toward the downstream side of the combustion exhaust gas flow, and a drain collecting part (58) is recessed at the lowermost part of the inclined part. The strongly acidic drain collected in the collecting part (58) passes through a drain pipe (59), flows into a neutralization device (not shown), is neutralized by the neutralization device, and is then discharged to sewage. It has become.
[0021]
The exhaust guide plate (56) is inclined toward the downstream side so that the combustion exhaust gas flows along the area where the heat absorbing pipes (13a) to (13d) are provided, and the downstream end is bent downward and hangs down. It forms a wall (560), and below the hanging wall (560) is an exhaust port (561) from the heat exchange chamber (12). An exhaust top (41) for discharging combustion exhaust to the outside of the machine is disposed above the front plate (53) constituting the casing (50).
[0022]
[Heat absorbing pipes (13a) to (13d)]
The heat absorbing pipes (13a) to (13d) located in the heat exchange chamber (12) formed between the drain guide (57) and the exhaust guide plate (56) are bent in the same waveform. .
As shown in FIG. 3, the heat-absorbing pipes (13 a) to (13 d) are one of corrugated pipes (tubes having an outer surface shape in which arc-shaped valleys and peaks are alternately continuous in the axial direction) made of stainless steel or titanium. It is curved in two planes (meandering surface) and has relatively large rigidity so that it is not easily deformed.
[0023]
The heat-absorbing pipes (13a) to (13d) include a folded portion (R) located at the center in the meandering direction, two straight portions (S) and (S) extending separately from both ends thereof, and the straight portion. (S) Two folded portions (R) and (R) having one end connected and integrated with (S), and straight portions (S) on both sides extending separately from the other ends of the folded portions (R) and (R). ) (S), and in the present embodiment, each of the folded portions (R) is formed in a semicircular arc shape. As a result, the heat absorbing pipes (13a) to (13d) have a folded portion (R) and a straight portion (S) following the end of the folded portion (R), which is a continuous waveform that is repeated within a meandering plane as one plane. Is formed.
[0024]
As shown in FIG. 5, each folded portion (R) of the heat absorbing pipes (13a) to (13d) has an oval cross-sectional shape obtained by flattening a circular pipe in a direction perpendicular to the meandering surface. I have. The figure shows a shape obtained by cutting a valley of the heat absorbing pipe (13a). On the other hand, the cross-sectional shape of each of the straight portions (S) of the heat absorbing pipe (13a) crossing the valley portion is circular as shown in FIG.
As shown in FIGS. 1 and 2, the heat absorbing pipes (13a) to (13d) are stacked in a direction perpendicular to the meandering surface, and among the heat absorbing pipes (13a) to (13d), The pipes are shifted from each other by a half pitch in the wavelength direction of the bent waveform. That is, in FIG. 1, the heat absorbing pipes (13a) and (13c) adjacent to the second and lowest heat absorbing pipes (13b) and (13d) are shifted by a half pitch in the downstream direction of the exhaust gas flow. It is provided in the part.
[0025]
Each of the heat absorbing pipes (13a) to (13d) is overlapped at a flattened folded portion (R) (R), and as shown in FIGS. 1 and 2, the heat absorbing pipe (13a) The overlapping portions (intersecting portions in plan view) of (13d) to (13d) are fixed together by binding metal fittings (16) (16) in the overlapping direction. Thereby, the interval between the heat absorbing pipes (13a) to (13d) is maintained at an appropriate interval over a long period of time, so that a decrease in thermal efficiency over time can be prevented.
[0026]
Also, side plates (51) and (52) serving as inner walls of the casing (50) are pressed against the outer periphery of the folded portions (R) and (R) of the heat absorbing pipes (13a) to (13d). Vibration of the heat absorbing pipes (13a) to (13d) due to the water hammer phenomenon is suppressed.
[0027]
Further, both ends of the heat absorbing pipes (13a) to (13d) penetrate outwardly through the side plate (52) of the casing (50) constituting the sub heat exchanger (5), and the heat absorbing pipes (13a). As shown in FIG. 2 and FIG. 6, the one end of each of the through holes (13d) is connected to an inflow header (31), and the inflow header (31) is connected to a water pipe. The connecting water supply pipe (33) is connected. On the other hand, the other ends of the heat absorbing pipes (13a) to (13d) are connected to each other by an outlet header (32), and the outlet header (32) is connected to the heat absorbing pipe (21) of the main heat exchanger (2). ) Is connected to a connection pipe (34) connected to the upstream end. As described above, the heat absorbing pipes (13a) to (13d) are connected at the both ends thereof by the inflow side header (31) and the outflow side header (32) and are connected in parallel as a whole. The flow resistance is reduced as compared with the case where the heat absorbing pipes (13a) to (13d) are connected in series.
[0028]
[Explanation of functions of each part]
In this apparatus, a hot water supply faucet (K) is connected downstream of a heat absorbing pipe (21) constituting a main heat exchanger (2).
When the heat absorbing pipe (21) and the like are brought into a water-flowing state by opening the hot water supply faucet (K), the air supply fan (F) rotates and the gas burner (B) burns in response to a signal from a water amount sensor (not shown) that detects this. start.
Then, the tap water as the fluid to be heated supplied from the water supply pipe (33) is supplied to the inflow side header (31) → heat absorption pipes (13a) to (13d) → outflow side header (32) → connection pipe (34) → heat absorption. Pipe (21) flows through a path connected to hot water tap (K).
[0029]
On the other hand, the combustion exhaust gas from the gas burner (B) receives the heat absorbing pipes (21) of the main heat exchanger (2) → the heat absorbing pipes (13a) to (13d) of the sub heat exchanger (5). → Exhaust port (561) → Flow through the path connected to the exhaust top (41). At this time, the sensible heat of the combustion exhaust gas is absorbed by the water flowing through the heat absorbing pipe (21) of the main heat exchanger (2), and the latent heat of the combustion exhaust gas whose temperature has been lowered by the heat absorption is converted into the sub heat exchanger (5). ) Is absorbed by the water flowing through the heat absorbing pipes (13a) to (13d). Then, the hot water heated and generated by these endothermic actions is supplied to the hot water supply faucet (K).
[0030]
On the other hand, the drain generated in the sub heat exchanger (5) by the latent heat absorption from the combustion exhaust is dropped on the drain guide (57) and is discharged from the drain collecting part (58) through the drain pipe (59). It is led to a neutralization device (not shown).
In this device, since the heat absorbing pipes (13a) to (13d) are overlapped at the flattened folded portion (R), the overlapping of the heat absorbing pipes in the entire heat absorbing pipe group is compared with that of the unheated pipe. The dimension in the direction is reduced, and the size of the sub heat exchanger (5) can be reduced.
[0031]
Further, since the heat absorbing pipes (13a) to (13d) are overlapped at the flattened folded portion (R), as shown in FIG. 7, the linear portions (S) of the heat absorbing pipes (13b) and (13d) are formed. The distance between the central axis and the central axis of the linear portion (S) of the heat absorbing pipes (13a) (13c) superimposed on the central axis in the superimposing direction is reduced. That is, when the group of the heat absorbing pipes (13a) to (13d) is projected in the direction of the exhaust flow, the straight portion (S) in the heat absorbing pipes (13b) and (13d) and the heat absorbing pipes (13a) and (13c). Is completely overlapped with the straight portion (S). Therefore, the heat absorbing pipes (13a) to (13d) are densely arranged, and the heat absorbing pipes (13a) to (13d) do not contact the heat absorbing pipes (13a) to (13d) as compared with the case where the disposing density is low. The amount of wasteful combustion exhaust discharged is reduced. In other words, the flowing combustion exhaust wraps around the heat absorbing pipes (13a) to (13d), thereby improving the thermal efficiency.
[0032]
In the above embodiment, the case where the present invention is applied as the sub heat exchanger (5) of the condensing water heater has been exemplified. However, the main heat absorbing the sensible heat of the combustion exhaust gas of the gas burner (B) has been described. The present invention may be applied to the exchanger (2). Further, the present invention may be applied to a heat exchanger in a bath kettle of a reheating circuit that circulates in a bathtub and a bath kettle, and the present invention may be applied to various heat exchangers in which a fluid to be heated flows. it can.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a water heater to which a heat exchanger according to an embodiment of the present invention is applied. FIG. 2 is a transverse sectional view of a sub heat exchanger (5). FIG. 3 is a perspective view of a heat absorbing pipe (13a). FIG. 4 is a sectional view taken along the line IV-IV in FIG. 3 FIG. 5 is a sectional view taken along the line VV in FIG. 3 FIG. 6 is a rear view of the sub heat exchanger (5) FIG. FIG. 8 is an explanatory view of an arrangement relationship of heat absorbing pipes (13a) to (13d). FIG. 8 is an explanatory view of a conventional example. FIG. 9 is an explanatory view of a conventional example.
(13a) to (13d) ... heat absorbing pipe (2) ... main heat exchanger (5) ... sub heat exchanger (50) ... casing (B) ... gas burner (R) ..Folding part (S) ... Linear part

Claims (5)

A group of heat absorbing pipes stacked in a state in which a plurality of heat absorbing pipes that absorb the heat of the combustion exhaust gas from the gas burner and through which the fluid to be heated flows intersect,
In a heat exchanger including a casing surrounding the heat absorbing pipe group,
The heat exchanger, wherein the intersecting portions in each of the heat absorbing pipes are flattened in the overlapping direction. In the heat exchanger according to claim 1,
Each of the heat absorbing pipes has a shape meandering in a waveform within one meandering plane,
The heat exchanger, wherein the heat absorbing pipes are sequentially stacked in a direction perpendicular to the meandering surface, and adjacent heat absorbing pipes in the overlapping direction are shifted from each other in the wavelength direction of the waveform. In the heat exchanger according to claim 2,
Each of the heat absorbing pipes is formed of a corrugated pipe curved to have the same waveform as each other, and has a continuous waveform in which an arc-shaped folded portion and a linear portion following an end of the arc-shaped folded portion are alternately repeated. It is composed,
The heat exchanger, wherein the flattened portion is the arc-shaped folded portion. In the heat exchanger according to claim 3,
Each of the arc-shaped folded portions is located in the casing,
A heat exchanger, wherein an inner wall of the casing is pressed against an outer periphery of each of the arc-shaped folded portions. In the heat exchanger according to any one of claims 1 to 4,
The heat exchanger, wherein the heat absorbing pipes are fixed to each other at the intersection.

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